Added some etcd retries to try to work around some flakes we see in Travis.

cmd/integration/integration.go

@@ -111,15 +111,29 @@ func startComponents(manifestURL string) (apiServerURL string) {
 	apiServer := httptest.NewServer(&handler)
 
 	etcdClient := etcd.NewClient(servers)
+	sleep := 4 * time.Second
+	ok := false
+	for i := 0; i < 3; i++ {
 		keys, err := etcdClient.Get("/", false, false)
 		if err != nil {
-		glog.Fatalf("Unable to list root etcd keys: %v", err)
+			glog.Warningf("Unable to list root etcd keys: %v", err)
+			if i < 2 {
+				time.Sleep(sleep)
+				sleep = sleep * sleep
+			}
+			continue
 		}
 		for _, node := range keys.Node.Nodes {
 			if _, err := etcdClient.Delete(node.Key, true); err != nil {
 				glog.Fatalf("Unable delete key: %v", err)
 			}
 		}
+		ok = true
+		break
+	}
+	if !ok {
+		glog.Fatalf("Failed to connect to etcd")
+	}
 
 	cl := client.NewOrDie(&client.Config{Host: apiServer.URL, Version: testapi.Version()})
 	cl.PollPeriod = time.Millisecond * 100